JPS5820603Y2 - Copy machine paper feed device - Google Patents

Description

[Detailed description of the invention] This invention is a paper feeding device for a copying machine having a double-feed prevention mechanism, in which a means for preventing curling of paper is provided between the double-feed prevention mechanism and the conveyance roller. Regarding improvements.

Conventionally, in a copying machine equipped with an anti-electro-transfer mechanism that prevents electro-transfer of paper, paper g, which is double-fed from paper tray B by paper feed roller a, is removed by a multi-feed system installed in the middle of the conveyance path, as shown in Fig. 1. After being separated by the prevention mechanism d, only one sheet of paper is conveyed toward the photoconductor via the second conveyance roller e, and the double-fed sheets either wait at that position for the next copy or are moved by the paper feed roller. Its position is not constant, such as waiting at position a.

Therefore, in the next copying process, the paper starts from an arbitrary position between the paper feed roller a and the vicinity of the double-feed prevention mechanism d, resulting in variations in paper feeding timing.

Conventionally, the paper feeding roller a and the paper feeding belt d rotate faster to cause the paper g to curl g' before the waiting second conveyance roller e, thereby absorbing the variation in paper feeding timing. ing.

However, with this method, the leading edge of the paper hits the second transport roller at high speed, and the amount of curl of the paper g in front of the second transport roller e before the rear end of the paper g is released from the first transport roller f. There is a problem where there are too many pages, causing paper jams.

In order to prevent this, the speed of the paper g can be controlled by making the speed of the first transport roller f slower than the paper feed roller a or the paper feed bell (d), but if the speed of the first transport roller f is not too slow, Then, a curl g'' occurs in the paper g between the first conveyance roller f and the double-feed prevention mechanism C, which also causes a problem of paper jam.

This invention was made for the purpose of improving such problems, and provides a paper feed device for a copying machine that is provided with a curl prevention means for preventing paper from curling between a double feeding prevention mechanism and a first conveyance roller. This is an attempt to eliminate the cause of paper jams during paper feeding.

Hereinafter, this invention will be described in detail with reference to an embodiment shown in FIG. 2 and subsequent figures.

In the figure, reference numeral 1 denotes a paper tray installed in a copying machine (not shown), in which a large number of sheets of paper 2 to be fed are piled up and stored. It is designed to be sent to

A paper feed belt 5 that rotates in conjunction with the paper feed roller 3 is provided in the middle of the conveyance path 4, and a double feed prevention mechanism 6 is provided below the paper feed belt 5.

The double-feed prevention mechanism 6 has a sorting belt 8 that is wrapped around a plurality of guide rollers 1 and rotates in the opposite direction to the paper feed belt 5.
It acts to control the object and hold it in that position.

Further, the paper 2 transported by the paper feed belt 5 reaches a first transport roller 9 provided close to the double-feed prevention mechanism 6 .

The first conveyance roller 9 consists of a pair of rollers 9 a t 9 b that are in pressure contact with each other while sandwiching the conveyance path 4, and has the function of further conveying the paper 2 in the direction of the second conveyance roller 10.
It rotates at a slower speed than the paper feed roller 3 and paper feed belt 5 to control the feeding speed of the paper 2.

A curl prevention means 11 is provided between the first conveyance roller 9 and the double feed prevention mechanism 6.

This curl prevention means 11 suppresses the curl of the paper 2 caused by the speed difference between the first conveyance roller 9, the paper feed roller 3, and the paper feed belt 5, and curves a part of the conveyance path 4 downward in an arc shape. Due to this curvature, the paper 2 is curved along the conveyance path 4, and a buckling force is generated on the paper 2.

Further, when the leading edge of the paper 2 hits the second transport roller 10, a force F as shown in FIG. ”, Fl, and F2 (determined by the pressing force and the coefficient of friction between the paper) are generated, and these forces F, F1, and F2 have the following relationship.

F2>F”)F.

Therefore, the buckling force (strength of the paper 20) of the paper 20 overcomes F, causing slippage between the paper 2 and the paper feed belt 50.

Note that the distance between the first conveyance roller 9 and the paper feed belt 5 is 70r.
It is desirable to set it to IrJn or less.

Further, the curl preventing means 11 keeps the conveying path 4 horizontal and provides a curl regulating plate (not shown) above the sheet conveying path 4.
It may also prevent curling.

On the other hand, the paper 2 conveyed on the conveyance path 4 by the first conveyance roller 9 reaches the second conveyance roller 10 through the opening 12a of the breadboard plate 12 provided on the conveyance path 4 in parallel thereto.
Furthermore, the image is transferred to a photoreceptor (not shown) by the second conveyance roller 10 and transferred thereto.

Note that 13 is a limit switch for controlling the amount of curl generated in front of the opening 12a of the baffle plate 12.

Since this invention has been described in detail above, in order to reduce the amount of curl of the paper 2 that occurs before the second transport roller 10, the speed of the first transport roller 9 is changed to the speed of the paper feed roller 3 and the paper feed belt 5. Even if it is slower, the stiffness of the paper 2 bent by the curl prevention means 11 causes slippage between the paper 2, the paper feed belt 5, and the double-feed prevention mechanism 6, and the paper 2 is not fed, resulting in a paper jam. This makes it possible to reliably prevent the formation of curls in the paper 2 between the first conveyance roller 9 and the paper feed belt 50, which would cause the paper 2 to curl.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional paper feeding device, FIG. 2 is a schematic diagram showing an embodiment of this invention, and FIG. 3 is an explanatory diagram of its operation. 1 is a paper tray, 2 is paper, 3 is a paper feed roller, 4 is a conveyance path, 5 is a paper feed belt, 6 is a double feed prevention mechanism, 9 is a first conveyance roller, 10 is a second conveyance roller, 11 is a curl Prevention measures.

Claims (1)

[Scope of utility model registration request] A paper feed roller 3, a paper feed belt 5, a double feed prevention mechanism 6, a first transport roller 9, and a second transport roller 10 are installed from the paper feed tray 1 side in the middle of the transport path 4 connecting between the paper tray 1 and the photoreceptor. are provided in sequence, and the feed speed of the first conveyance roller 9 is slower than that of the paper feed roller 3 and the paper feed belt 5. By giving the paper 2 a curvature in between, the paper 2, the conveyor belt 5 and the double feed prevention mechanism 6
A paper feeding device for a copying machine, which is provided with a curl prevention means 11 that causes slippage between the sheets.